Optical device for advertising or other purposes.



No. 719,771. PATENTED FEB. 3, 1903. R. G. T. EVANS. OPTICAL DEVICE FORADVERTISING OR OTHER PURPOSES.

APPLICATION FILED r33. 27, 1902. nnnnwnn 1220.31, 1902.

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m'fiwesses I Inwafir 1?. a wi y ans m5 norms PETERS o0, PHOTO-H1140msmnerm o UNITED STATES PATENT OFFICE.

ROBERT CECIL TURLE EVANS, OF LONDON, ENGLAND.

OPTICAL DEVICE FOR ADVERTISING OR OTHER PURPOSES.

SPECIFICATION forming part of Letters Patent No. 719,771, dated February3, 1903. Application filed February 27, 1902. Renewed December 31, 1902.Serial No. 137,374. (No model.)

To rtZ/X whom it may concern:

Be it known that I, ROBERT CECIL TURLE EVANS, a subject of the King ofGreat Britain, residing at 9 Heathcote street, Grays Inn road, London,England, have invented certain new and useful Improvements in OpticalDevices for Advertising or other Purposes; and I do declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertainstomake and usethe same.

It is well known that if a ray of white light is caused to pass througha transparent prism this ray of light is bent and resolved into itscomponent colors, so as to form a band of colors or spectrum which maybe projected onto a screen. If, on the other hand, the process bereversed and such a band of colors be looked at through a prism, thesesmall patches of color will be apparently superimposed on one another ata point apparently some distance away from the colored band, and the eyewill there behold a patch of white light. If isolated patches of coloredmaterial be gazed at through a prism, these patches will apparentlyshift away from their actual position, the apparent position being nearor farther away from the actual position, according to whether theybelong to the red or the blue end of the spectrum, respectively.

My invention consists in applying this principle as discovered by SirIsaac Newton to the manufacture of an optical device or toy primarilyintended to be employed for advertising purposes.

In carrying the first part of my invention into effect I provide abackground of cardboard or other suitable material and preferably of adull-black color, having what is popularly known as a matte surface, andaffix thereto or paint thereon various brightlycolored bars or stripsadjusted at such intervals and at such angles to one another that whenviewed through asuitably-mounted prism the actually irregular bars ofcolor apparently shift with respect to the background and to one anotherto the right or to the left or up and down, as the case may be, so as toform apparently continuous or con nected bars of color. The varioussquares or bars of color may easily be so arranged with respect to oneanother on the background that when viewed through a prism they take uppositions so as to form letters or designs, which without the aid of theprism would be quite illegible.

According to a modification of my invention I arrange letters of variousprimary col- -0rs on a background in such a manner that though eachindividual letter may be read with the naked eye the sequence of theletters cannot easily be ascertained until the device is viewed througha prism, when, owing to the apparent moving of the letters of certaincolors with respect to the others, the sequence may readily be made out.

In order that my invention may be readily understood, I will now referto the accompanying drawings, which show diagrammatically two examplesof designs, in these cases letters, prepared in accordance with theinvention and also two preferred constructions of a prismatic applianceto be used for viewing them.

Figure 1 represents an arrangement of colored squares and strips asactually prepared, the respective colors being indicated byreference-letters and by varied hatching, as will be describedhereinafter; and Fig. 2 represents approximately the result as seenthrough a prism. Figs. 3 and 4 are similar views to Figs. 1 and 2, butshowing an example of one letter becoming another when viewed through aprism. Fig. 5 is a section of a'simple form of prismatic device forviewing the designs, and Fig. 6 is a section of a modified form in whicha mirror is combined with the prism.

Referring first to Figs. 1 and 2, it will be seen that in the actualdesign, Fig. 1, the colors red, green, and white (indicated by thereference-letters R, G, and W, respectively, and by varied hatching)alone are employed, the background being preferably a dull black, asalready mentioned. When viewed through a prism, the red and greenlight-rays are differently refracted, and from the white square acomplete spectrum is obtained, the result being apparent movements, butof different degree, of the squares and strips, combined with theproduction of very attractive color phenomena. Consequently the actualthree-color disorderly and apparently meaningless design becomes aclearly-defined manycolored designin this case the letter I. The coloreffects, which cannot be set forth on the drawings, result partly fromthe apparent superimposition of one color upon an other and partly fromthe dispersion of colored light-rays which the prism effects even whenthe object viewed is apparently monocolored.

In the design shown in Fig. 3 the phenomena of refraction and dispersionare utilized to give an erroneous effect, for although the actual letteris T, when viewed through a prism it becomes the letter F, the greensquares with modified colors apparently moving to the end ofthe red barto form the upright of the letter and the white square elongating to acomplete spectrum to form the halfway bar. Similarly other designs, moreor less complicated, may be prepared, so that from a disorderly ormisleading collection of colored bars and strips an advertising design,word or phrase, or picture may be revealed when observed through a prismwith color effects not visible with the naked eye. The letters ordesigns may also be so arranged that the parts of one are mixed with theparts of the next, but when viewed through the prism they separate outand the actual confusion becomes order. Moreover, by combining with theprism a mirror, the reversing properties of which are well known, it ispossible to so arrange that the letters or designs are reversed right toleft or upside down to produce the advertisement or the like.

Although I have described only the use of three colors-red, green, andwhite-0n a black background, other colors, suitably selected accordingto their refractive indices, may of course be employed, and thebackground may be other than black, the result being further strange andinteresting color phenomena; but whatever the colors may be theprinciples set forth above will govern their selection and arrangement.Also in some cases I may take advantage only of the color phenomena ofrefraction, making the letters or designs all of one color, orapproximately so, in which case they appear with new colors when viewedthrough the prisms, and the eifect is furthermore enhanced by a shadingwhich appears under these conditions.

A further part of my invention refers to the optical instrument by meansof which such colored inscriptions, designs, &c., may be read or madeout. I provide a paper or cardboard tube open at both ends andmeasuring, preferably, about one and one-half to two inches in lengthand of about two-thirds of an inch in diameter. Close to one end andinside this tube I arrange a small triangular glass prism, with its axisat right angles to the axis of the paper tube, and between this prismand the opposite end of the tube the tube is unobstructed to leave aclear space for the passage of the light-rays. That end of the tubecontaining the prism may or may not then be covered with a cover havinga small circular aperture for the eye. On applying the eye to the end ofthe tube nearest that at which the prism is situated and gazing throughit in the direct-ion of such a device as those before mentioned andmoving the tube about slightly in different directions the device willcome into view. The tube must then be held still and rotated upon itsown axis until the device can be read.

In Fig. 5 I illustrate a very suitable form of the prismatic device. Itconsists of a tube a, of metal, cardboard, or the like, having near oneend a prism 17, mounted. A cover having an eye-aperture may be provided,if desired. The direction of vision is indicated on the figure.

In Fig. 6 I show the combination, with the prism 17, of a mirror 0 foruse as already set forth. Any suitable prismatic device may, however, beemployed or a plain prism, also a double device may be used having twoprisms, one for each eye, as in a stereoscope, to enable stereoscopicobservation to be made.

What I claim as my invention, and desire to secure by Letters Patent,is-

An optical device for advertising purposes, consisting of strips or barsof different colors, systematically arranged to produce apparentdisorder, the various colors being so selected and relatively located inthe system as to produce an orderly and intelligible arrangement whenviewed through a prism, substantially as and for the purpose described.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

ROBERT CECIL 'lUllLll EVANS.

Witnesses:

ROGELIO PLAZA, JOHN FRANCIS GAIRNS.

